U.S. Pat. No. 6,932,058 discloses a carburetor for an internal combustion engine wherein the carburetor has a switchable valve. The switchable valve is mounted in a fuel path which leads from a storage space and is connected to a main fuel opening. From this fuel path, a further fuel path branches off downstream of the valve and this further fuel path feeds an idle system and a part-load fuel path. The controllable valve thereby controls the total fuel quantity supplied to the intake channel.
It has been shown that an inadequate fuel supply can take place in some operating states, especially, in transitional states.